I’m trying to control (turn on and off) a 3-volt LED board (powered by two AAA alkaline batteries) using a 5 volt Arduino Pro Mini.
The controller board for the LEDs has a small unlabelled microcontroller on it, and is pretty low power (just 4 dim white LEDs). I can’t tell if it has any voltage regulation. A pic is attached (the pads at bottom center are + and -).
There’s a switch connecting the LED board to two AAA batteries, that interrupts positive.
I’m wondering what the best and/or easiest way to control that is? (And by “control” I mean simply turn it on and off).
Could I possibly use a resistor to power the LED board directly from the Arduino’s 5 volt pins?
Or would it require using a transistor? I have some TIP120 transistors and was considering using it as a project to learn to use those. If so, are these good instructions for this project?
Or if I used the 3.3 volt version of the Arduino Pro Mini could I likely power the board directly?
Thanks for any help.